There are provided a device and method for providing a mobile Internet call service. In order to reduce a call waiting time for an mVoIP call, when a call is an initial call after power of a terminal is turned on or using the main call number, information for a call connection is acquired in advance and a light weight session is maintained. When the mVoIP call is made later, the maintained light weight session is used to make a direct P2P call. Therefore, it is possible to reduce a call connection time. As a result, when the mVoIP call attempt is made, a call waiting time is significantly reduced and thus it is possible to provide a rapid response and improve user satisfaction. When the light weight session is maintained, access to a separate server system is not performed. As a result, it is possible to connect a P2P call even when call traffic is heavy.